Students can use web-based data sets to investigate long-term global change. By accessing, graphing, and interpreting available greenhouse gas, population, oxygen isotope, and temperature data sets, students can compare data that span two distinct time invervals: the last few hundred thousand years. Data for the last 250 years can be examined to investigate relatively recent trends in atomspheric CO2, population, and temperature. Data for the last 250,000 and 450,000 years demonstrate the use of isotopes as a proxy for temperature, the existence of climate cycles, and long-term changes in atmospheric CO2 and temperature. The activity begins by posing an open-ended question that makes study of global change relevant to students. Students complete the activity by using their interpretations to compose a brief written report. Technical, problem solving, and communication skills are all emphasized in the inquiry-based activity.

Full Text(Acrobat (PDF) 7.4MB Mar11 05)URL for this article: http://www.nagt.org/nagt/jge/abstracts/nov02.html#v50p497

Courses designed around student-learning pose a unique set of challenges. Instructors must consider how students learn content and construct meaningful knowledge out of it. Course planning needs to address the linkage between learning objectives and skill development, and include appropriate assessment strategies. These issues go beyond designing effective components such as collaborative learning and writing-to-learn exercises, although these and other strategies may be essential components of a student-learning course. Course planning must address how to integrate these strategies to achieve the progressive development of students skills and abilities in a manner that facilities learning course content. Assessment tools need to be calibrated to monitor student development and identify students ultimate level of understanding. In addition, students need opportunities to honestly communicate their perspective on their progress and the course progression. This feedback allows instructors to remain responsive to learning issues, thereby giving value to student concerns. Related Website: Mark Harris's Home Page

Full Text(Acrobat (PDF) 81kB Mar11 05)URL for this article: http://www.nagt.org/nagt/jge/abstracts/nov02.html#v50p515

Understanding the Origin and Meaning of the Radioactive Decay Equation
Stephen P. Huestis
Department of Earth and Planetary Sciences
University of New Mexico
Albuquerque, New Mexico

The radioactive decay equation can be derived, as an exercise in calculus and probability, as a consequence of two physical principles: a radioactive nucleus has no memory, and decay times for any two nuclei of the same isotope are governed by the same probability distribution. The first principle implies that this distribution has a continuous exponential probability density function. Then, knowing the probability of survival of a single nucleus to a specified time, the second principle allows the number of a collection of nuclei surviving to this time to be treated as a random variable governed by the discrete binomial distribution. The familiar radioactive decay equation does not give the actual number remaining at this time, but rather the expected value of this distribution. With this proper interpretation of the radioactive decay equation, the number of nuclei need not be a large. Algebraic and numerical experiments illustrate, however, that as the number of nuclei grows to the large values associated with geochronological studies, the probability of significant departure from the expected value becomes negligibly small.

Full Text(Acrobat (PDF) 286kB Mar11 05)URL for this article: http://www.nagt.org/nagt/jge/abstracts/nov02.html#v50p524

Although GPS technology has greatly improved in recent years it is still important to train students in traditional navigation skills with the Brunton compass. In addition to considerable pedagogic value inherent in such training, the compass can serve as a valuable backup to GPS. Within the geosciences the pace and compass traverse has been a common field technique for determining spatial coordinates of features in the field. However, students commonly find it difficult to separate graphical errors inherent in the technique from those associated with field measurements. The Pace program takes user-supplied azimuth and distance data and employs simple vector addition to determine the XY coordinates of successive stations in a traverse. This program provides a way for students to eliminate graphical errors, thereby allowing them to better gauge the true accuracy of their field data. Instructors can also use the program as a valuable means of helping students learn to differentiate between random and systematic errors in their field-data set. Ultimately, students should realize that multiple sources of error exist in most types of data and appreciate the importance of locating and minimizing such errors.

Full text(Acrobat (PDF) 3.4MB Mar8 05)URL for this article: http://www.nagt.org/nagt/jge/abstracts/nov02.html#v50p528

Problems and Suggestions Related to Soil Classification as Presented in Introduction to Physical Geology Textbooks
Eric Brevik
Department of Physics, Astronomy, and Geosciences
Valdosta State University
Valdosta, GA

Complex concepts and ideas are often presented to introductory level students in a simplified form for educational purposes. This simplification sometimes requires that the "whole truth" not be presented. However, the simplified material should be current and factual to the extent that future lessons that build on the introductory material will expand on the originally presented material rather than contradicting it. The presentation of soil classification in many current introductory physical geology textbooks is over 35 years out of date. In addition, the way soil classification terminology is used would be questionable even if it were still current. Individuals teaching introductory geology courses that include sections on soils and the authors of textbooks using incorrect classification terminology should obtain current references on soil classification and correct these deficiencies.

Full Text(Acrobat (PDF) 1.2MB Mar11 05)URL for this article: http://www.nagt.org/nagt/jge/abstracts/nov02.html#v50p539

A Computer Program for Use with Pace and Compass Exercises
James Reichard
Department of Geology and Geography
Georgia Southern University
Statesboro, GA

Although GPS technology has greatly improved in recent years it is still important to train students in traditional navigation skills with the Brunton compass. In addition to considerable pedagogic value inherent in such training, the compass can serve as a valuable backup to GPS. Within the geosciences the pace and compass traverse has been a common field technique for determining spatial coordinates of features in the field. However, students commonly find it difficult to separate graphical errors inherent in the technique from those associated with field measurements. The Pace program takes user-supplied azimuth and distance data and employs simple vector addition to determine the XY coordinates of successive stations in a traverse. This program provides a way for students to eliminate graphical errors, thereby allowing them to better gauge the true accuracy of their field data. Instructors can also use the program as a valuable means of helping students learn to differentiate between random and systematic errors in their field-data set. Ultimately, students should realize that multiple sources of error exist in most types of data and appreciate the importance of locating and minimizing such errors.

Full Text(Acrobat (PDF) 776kB Mar11 05)URL for this article: http://www.nagt.org/nagt/jge/abstracts/nov02.html#v50p544

A new software package, EnviroLand, is available for teaching chemical speciation of acids and bases in environmental chemistry and geochemistry. The program is appropriate for undergraduate and graduate instruction. EnviroLand has been used in a variety of ways including as an inquiry-based exercise, as a lecture aid, a system for checking spreadsheet logic and calculations, and a key to homework assignments. Computer-assisted instruction is rapidly becoming a common tool in the classroom, but software packages should be designed to be interactive so that student learning will be enhanced.

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Our teacm has developed a user-friendly software package EnviroLand, for teaching hydrological fate and transport concepts to undergraduate students. We have successfully used this program in introductory Earth science courses, environmental chemistry, geochemistry, and geohydrology. EnviroLand contains basis transport models for river, lake, and groundwater systems and can be used to simulate the transport of pollutants under a variety of conditions. A free copy of EnviroLand can be downloaded from Educational Solutions LLC.

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A Visual Basic 6 Program that Facilitates Learning the Characteristics of Simple and Pure Shear through Experimentation
Gary Girty, Nathaniel Reish, Patricia Baroek, Brett Heitman, Kesler Randall, Daniel Lilly, and Christopher Lynch
Department of Geological Sciences
San Diego State University
San Diego, CA

Visualizing Strain, a Visual Basic 6 program with Graphical User Interface, was developed to allow students a means of discovery through experimentation. The program allows students to conduct simple and pure shear experiments. Both of these strain types are produced when the area (or in 3D, the volume) of an object does not change during a distorting event.
The mathematical background necessary for students to fruitfully use Visualizing Strain is typically gained in a high school algebra class. Hence, Visualizing Strain is appropriate for both introductory geology and structural geology courses.
Using Visualizing Strain, students can produce sophisticated strain models that simulate the distortions of the circular cross sectional area of a crinoid columnal.

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Using Online Homework to Engage Students in a Geoscience Course for General Education
Karen Grove
Department of Geological Sciences
San Francisco State University
San Francisco, CA

Online homework assignments, named Virtual Voyages, were designed to more actively engage students with the course material in a large-sized, lower-division geoscience course for general education. The assignments implement the learning cycle by having students engage in explorations of real-world data before they attend class, where concepts are presented and applied. Students access the voyages via the internet, and use course-management software to answer questions and receive their scores online. The Virtual Voyages consist of informational images and text; multiple-choice questions that are automatically graded, and short-answer questions that the instructor grades online. Because students are introduced to topics before class, they come to class better prepared and more willing to participate in discussions. Students have responded favorably-they describe the assignments as an effective learning method, a primary reason for recommending the course to others, and a tool that makes learning more fun-and exam scores have improved since voyage implementation. The Virtual Voyages were developed for an ocean science course, but the technique could be applied in any geoscience course.Related Website: The Ocean that Surrounds Us

URL for this article: http://www.nagt.org/nagt/jge/abstracts/nov02.html#v50p999

Structural geology courses at Wheaton College in northeastern Illinois conclude with a three-week geologic mapping simulation. It is preferable to have class participants learn basic mapping skills in the field. However, time and geographic constraints are such that the Geology Department now resorts to an indoor exercise as a prelude to the required summer field camp.

The Geology Department's large basement lab space provides a flexible environment to create an artificial field area. Books, color coded to a set of distinctive hand specimens, are distributed throughout the room in patterns representing geologic-suite outcrops. These in turn correspond to a diversity of tectonic terranes. Books are oriented so as to portray structural information. Structural and petrographic data enable the students to synthesize a geologic map, cross sections, annotated geologic column, and ultimately, a report of investigation with historical narrative. Several years' experience indicates that the simulations meet or surpass expectations. Participants enjoy the puzzle-like challenge and integration of concepts. Those who have completed the exercise are typically more confident and able to synthesize data during actual field work than those who have not.

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Tabletop models were created from common materials to demonstrate concepts in direct current electrical resistivity, self potential and electromagnetic geophysical methods. The models can be used as a laboratory exercise or as a classroom demonstration. Data profiles over the models are similar to those computed from equations and from field examples. The signals are generated with a function generator or battery and are measured with a digital multimeter. The experiment is greatly facilitated by using a multimeter that can be connected to the serial port of a computer. The tabletop models reinforce concepts learned in basic physics, introductory geology and geophysics, and environmental engineering courses.

Full Text(Acrobat (PDF) 1.9MB Mar11 05)URL for this article: http://www.nagt.org/nagt/jge/abstracts/nov02.html#v50p594